Heart disease has increased over the past 40 years, with little focus towards prenatal development. Maternal behaviors and in utero environment influence offspring development and health into adulthood. Recent research finds that exercise during pregnancy may be beneficial to fetal and infant heart development, evidenced by decreased resting heart rate (HR) and increased heart rate variability (HRV). Previous studies have mainly examined a population of women including those previously active. It is not known, however, if infants will still have favorable outcomes in unfit women that begin to participate in exercise while pregnant. The purpose of this research is to determine the benefit of maternal exercise in unfit women on infant heart health. We hypothesize that offspring of unfit women who exercise during pregnancy will have lower HR and higher HRV than (age-matched) offspring of unfit women non-exercisers. To address this question, unfit women were randomized to either exercise intervention or no intervention (controls) from 16 weeks of gestation until delivery. After delivery, women returned for HR and HRV measures on the one-month old infants.
Our current results show that exercise of unfit pregnant women decreased 1-month infant HR relative to same age infants of controls. Additionally, exercise of unfit women during pregnancy is associated with trends of increased measures of 1-month infant HRV compared to unfit controls. All measures of HRV are higher in exercise exposed relative to control infants. Our preliminary findings of lower HR and increased HRV, indicators of decreased heart disease risk, suggest that children of unfit women that exercise during pregnancy can experience similar heart and maturation benefits as children of women previously healthy and trained prior to pregnancy.
Our research is pivotal in encouraging all women, regardless of previous activity level, to begin exercise during pregnancy to improve the heart health of children prior to birth. This supports the idea of prenatal programming and further supports the use of exercise during pregnancy as a low-cost prevention/intervention for heart health of the next generation.